Na13K4Ga47.45: a New Sodium Potassium Gallide Phase Containing Trimeric Icosahedral Gallium Clusters

Na13K4Ga47.45 was isolated from a melt prepared from the elements taken in atomic proportion 3:1:12. It crystallizes in the trigonal R\overline{3}m space group [a = 16.325 (3), c = 35.135 (5) A]. The structure results from the packing of icosahedral Ga12 units and trimeric Ga28 units. The latter are formed by the condensation of three Ga12 units by triangular face sharing. Inter­polyhedral space is filled with K+ and Na+ cations.